[R-sig-Geo] Using "Mask" for SDMs (Maxent) with Dismo

[Johannes Radinger]

Hi,

I have several environmental rasters (loaded as stack/brick) in R which I want to use as predictors for Species Distribution Models (preferably Maxent) with the dismo-package. Some of the predictors are habitat specific variables and are restricted to a river (like a line of raster cells, all land is NA) while others cover the total spatial extent (climatic variables). Thus I've also created a raster MASK which indicates the cells that have values (that are non-NAs) in ALL maps.

Now I've two questions:
1) How can I use such a MASK within e.g. maxent to restrict my background points and predictions etc. only to these cells?
2) How can I simply exclude presence points that are outside these masking raster cells? I want only those samples (presences of my species) that are sampled within my defined rivers.


Thank you,

Johannes
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